Inverted hydropulse



July 17, 1962 F. ZWICKY INVERTED I-IYDROPULSE 4 Sheets-Sheet 1 Filed Aug. 11, 1950 TO FUEL TIMING SYSTEM TO FUEL TIMING SYSTEM IN VEN TOR FRITZ Z W/CK Y A TTORNEY July 17, 1962 F. zwlcKY 3,044,252

' INVERTED HYDROPULSE Filed Aug. 1]., 1950 4 Sheets-Sheet 2 -T0 FUEL TIMING SYSTEM TO FUEL TIMING SYSTEM IN VEN TOR. FRITZ Z W/CK Y J-MW A TTORNE Y Patented July 17, 1962 United States Patent Ofiice r. 3,044,252 INVERTED HYDRGPULSE Fritz Zwieky, Pasadena, Calif, assignor, by mesne assignments, to Aerojet-General Corporation, Cincinnati, Ohio, a corporation of Ohio Filed Aug. 11, 1950, Ser. No. 178,840

' 13 Claims. (Cl. 60-35.5)

This invention relates to jet propulsion units of the type adapted to be propelled through a fluid medium, particularly water, and has for an object to provide a device of this character capable of operation as a pulsing unit; that is, with reaction pulses established at a timed rate.

A related object is to make use of water-reactive fuels, herein called hydrofuels, and to use efiiciently the heat of reaction developed when the hydrofuel comes in contact with the water, regardless of the. pulsing rate.

A further object is to permit the use of hydrofuels which are normally solid.

'Jet propulsion through a fluid medium such as water is well known; and it is furthermore known how to react the fluid or at least a part of it, with a propellant substance. The reaction or combustion produces volumes of gases which force the excess luid together with the reaction products out through an exhaust opening in the rearward direction at high velocity, thereby generating the propulslveforce.

Such a jet propelled device suitable for operation in a water medium is covered in my copending application Serial No. 550,693, filed August 23, 1944, which issued as Patent No. 2,914,913, on December 1, 1959. In that application there is disclosed a device comprising a duct having an inlet opening and an exhaust opening, the inlet opening being provided with an automatic valve for regulating the flow of water through the duct. Hydrofuel is introduced at a timed rate into the water flowing through the reaction region of the duct, so that the explosions or reactions take place in timed intermittent pulses. Such a device has become known as a hydropulse.

Another form ofjet propulsion device for operation through water is disclosed in my copending application Serial No. 95,493, filed May 26, 1949, now abandoned. This device comprises an open chamber within the duct containing a water-reactive substance, and the inlet to the duct need not have any inlet valve.- Water present in the duct freely enters the chamber and contacts the hydrofuel therein. The contact produces a reaction or'explosion, forcing products of reaction and the water out of the chamber. 7 When the pressure of the explosion has subsided, water reenters the chamber, creating another explosion. These intermittent explosions with water correspondingly flowing into and out of the chamber take place at a natural resonant frequency determined by dimensions and characteristics of the construction. Accordingly, such a device has been called a hydroresonator, which term distinguishes it from the timed pulsing operation of the hydropulse.

My present invention, like that of my above-mentioned copending application Ser. No. 550,693, is of the hydropulse type, rather than the hydroresonator type. It difiers from the hydropulse of my copending application 550,693, however, in provision of an open combustion chamber or chambers within the duct within which the water reactive fuel is injected; and water present in the duct is allowed to flow into the chamber to contact water reactive propellant injected thereinto at a timed rate. The timing of the propellant determines the rate of the pulses; and in this respect it is similar to the hydropulse of my said prior application 550,693. The action, however, is inverted with respect to that of my said prior application, since in the present application the water flows into the chamber to meet the fuel; and the fuel is not injected into water, as in my said prior application; Accordingly, I

chamberat the time of entry of the fuel, to substantially the amount required for the reaction, a high efliciency will be obtained at the chamber; and the chamber will operate at a higher temperature than otherwise, thereby making possible the use of normally slower reacting fuels.

A feature of the invention is that it permits the use of hydrofuels which are normally solid at ambient temperatures; and the high temperature in the reaction can melt them without the need for additional heat.

A related feature is the provision of an auxiliary fuel feed system to introduce solid hydrofuels into the reaction chamber; and this auxiliary system may be used in addition to the hydrofuel supply system.

Another feature is the feeding of water reactive fuel 5 into the chamber intermittently at a timed rate, to determine the rate of the explosions.

Further features relate to the provision of valve means or channel barriers in association wtih the chamber openings to limit or control the admission of water into the chamber or chambers.

The arrangement according to my invention has the advantage that it enables the use of hydrofuels which could not heretofore =be eifectively used in such jet propelled devices due to their relatively slow reactive speed at the temperature and pressure which has heretofore existed in thereaction region of such devices.

The foregoing and other features of my invention will be better understood from the following detailed description and the accompanying drawings of which:

FIG. 1 shows a form of inverted hydropulse device according to my invention;

FIG. 2 shows another form of device in accordance with my invention;

FIG. 3 shows another form of inverted hydropulse according to my invention;

FIG. 4 shows a modification of the device of FIG. 3 in which the entry nozzle is provided with a valve; 'FIG. 5 shows a front view of the inlet valve used in FIGS. 1 and 3;

FIG. 6 is a perspective view of a valve blade used in the inlet valve of FIGS. 1 and 3;

FIG. 7 shows the manner in which the valve blade of 7 FIG. 6 isas'sembledbetween two channels;

FIG. 8'is a perspective view of'the valve blade of FIG. 6 and the channel with the valve blade partially cutaway to afford a view "into the lower side of the channel member;

;FIG. 9 is a view partly in' section showing the valve assembly surrounding the reaction'chamber of FIG. 2;

FIG. 10 is a view showing the valve assembly suractive metals of low atomic weight such as lithium, sodium, magnesium, silicon, potassium, boron, aluminum, beryllium, alloys of above metals, such as sodium potassium alloy, alloys of magnesium and aluminum, light metal hydrides such as boron hydrides BQHG, B H etc., lithium hydride and any other hydrides of the abovenamed metals, a combination of hydrides such as lithium aluminum hydride, light metal borohydrides, such as lithium borohydride or aluminum bo-rohydride, and also water reactive organo-metallic compounds such as zinc dimethyl, zinc diethyl, aluminum trimethyl, and aluminum triethyl.

The apparatus shown in FIG. 1 comprises a duct 11 having an inlet opening 12 and an exhaust opening 13. A valve such as, for example, a reed valve 14 is placed in the inlet opening and controls the flow of water through the duct in such a manner that when the pressure within duct 11 is greater than the pressure of the surrounding medium, valve 14 remains closed; and When the pressure within the duct drops to a value lower than the surrounding medium, the valve automatically opens, permitting water to flow through the apparatus. Rearwardly of valve 14 there is provided a reaction chamber 15 which is preferably positioned symmetrically with respect to the longitudinal axis of the duct. Reaction chamber 15 is closed at the front end, but is open at the rear end 16, except for an arrangement of channel valves 17 covering the rear end that serves as a directional barrier. The chamber opening 16 faces rearwardly substantially in the direction of the longitudinal axis of the duct, and the gases generated within the reaction chamber escape through this directional barrier which passes the gases travelling rearwardly with relative ease, but which serves .to impede the return of water into the reaction chamber after each charge of gas is exhausted. This tends to introduce an adequate amount of water at the proper time Within the reaction chamber.

A liquid propellant, which in the present case is a hydrofuel stored in a container 18 (FIG. 13), enters the reaction chamber through a conduit 19 and a nozzle 20 through which it is sprayed into the reaction chamber. Since the hydrofuel is water reactive, it will decompose spontaneously on contact with any water within the reaction chamber, thereby generating heat and gas.

In some instances it may be desirable to employ a water reactive substance in addition to the liquid hydrofuel, and this may comprise a solid metallic hydrofuel such as, for example, lithium metal, or other light metal alloy. This may be accomplished by providing a wire feeding mechanism 21 which may be of a well-known type, such as is commonly employed in feeding wire and the like; and this may be used to feed into the reaction chamber a wire 22 of the metal. The heat developed by the reaction between the hydroful and the water is considerable and is suflicient to cause the metal of the wire to melt as it enters the reaction chamber; and the molten metal coming into contact with the water decomposes, generating hydrogen and metal oxide.

The reed valve 14 employed in the forward end of the duct may be of a suitable construction which performs the functions noted above. A suitable form is shown in FIGS. 5, 7, 8, 9 and 10; it comprises an assembly of flexible blades and rigid channel members 31. Each rigid channel member 31 comprises a rectangular plate 32, the upper face of which is provided with a curvature as shown in FIGS. 7 and 8. The lower surface of plate 32 is provided with a number of channels 33 formed by channel partitions 34 which are integral with the plate 32 and run parallel with each other as shown. These channel partitions 34 taper in depth being deepest at the leading edge 35 and decreasing in depth as they approach the rear edge 36, in such a manner that the channel disappears entirely at edge 36. Each blade 30 is preferably rectangular as shown in FIG. 6 and corresponds in dimensions to the size of channel member 31.

FIG. 7 is a perspective view illustrating the manner in which a flexible blade 30 is sandwiched between two adjacent channel members 31; the detail of thechannel member 31 being brought out more clearly in the illustration, FIG. 8, which shows the appearance of the memher from below.

The arrangement of the assembled valve is such that the lower edge 37 of all the channel partitions 34 of each channel member reposes flatly against the surface of blade member 30. By this assembly arrangement the rear edges of the flexible blades 30 are free to vibrate and in doing so alternately Contact and move away from the rear edge 36 of channel member 31. This creates the valve action, the valve being closed when the blade edge 38 is against the rear edge of the channel member 36. When the valve assembly is complete the plurality of flexible blades alternately interleave between the several channel members 31, and the entire valve assembly is held near its leading edge 39, between the leading edges 35 of each channel member 31 and the front flat surface of the next channel member below it. The valves and channels are still further bound together by a purality of long bolts 40 which pass through holes 41 and 42 in the valve members and blades respectively. This assembly arrangement is shown more clearly in FIGS. 1 and 5, which shows the alternate channel members 31 and flexible blades 30 stacked within the conduit space through which fiuid will flow. In this manner the valve controls the flow through this portion of the conduit.

Whenever the pressure on the fluid at the discharge side of the valve 14 is greater or equal to the pressure acting on the valve at the entrance side, the flexible blades will remain closed, preventing a reverse flow of liquid through the valve assembly. As soon as the pressure on the discharge side becomes less than that acting on the entry side of the valve, the flexible blades will be pushed away from the tops of the partition members and permit flow of fluid through the valve assembly.

The directional barrier used at the rear end of the reaction chamber may conveniently be of a louver type construction. The directional barrier 45 is mounted on an annular support 46 which fills the entire area described by the circumference of the channel. The louver construction is shown in detail in FIG. 12 which shows a small portion of two of the U-shaped sections 17 which are arranged in the same relative position to each other that they will be assembled when placed within the ring 46. The sections are positioned within the ring 46 in such a manner that the bottom curve of the U is directed toward the forward end 48 of each of the reaction chambers, in this manner providing a more streamlined flow through the louver section from the reaction chamber. The slots 49, between each pair of U-shaped sections are placed longitudinally and run substantially across the entire width of the channel ending at the annular support 46. In this manner the central sections of the directional barrier become a minimum at the top of the area described by the annular support. The ends of the U-shaped sections are cut to conform to the annular support 46 and are secured to it by any suitable means uch as welding, brazing and bolting.

A function of the directional barrier in the rear of I the firing chamber or reaction chamber is to prevent the rapid entry of water into the firing chamber during the period when a new charge is being introduced into the reaction chamber from the liquid propellant tank 18. Furthermore, the directional barrier 45 tends to retain a portion of the peak pressure, developed during the reaction of the hydrofuel with the water, for a longer period of time, in effect permitting the subsequent reaction between the hydrofuel and the water to take place in the region of elevated pressure.

The modification shown in FIG. 2 is somewhat similar to that of FIG. 1, but in FIG. 2, the reed valve 14, instead of being at the front of the duct, as in FIG. 1,

is placed across the duct at a position around the rear end of the reaction chamber; and the valve structure provides a support for the chamber.

Since the reed valve assembly surrounds the reaction chamber, the valve assembly construction will be modified somewhat from the construction used in FIG. 1. The central portion of the valve assembly is cut away forming a circular opening through which is inserted the reaction chamber 15.

One form of apparatus suitable for causing the periodic injection of the fuel into the combustion chamber is illustrated in FIG. 13. A propellant tank 18 is connected to 'a gear pump 51 by conduit 50; Gear pump 51 may be driven by any convenient means such as a gasoline motor 62 The discharge from the gear pump 51 flows into a branched conduit 52. One branch 54 leads to a needle valve 56 and the other branch 55 connects the gear pump 51 to a constant pressure relief valve 53 of a suitable type such as is well-known in the art. Any discharge from the pressure relief valve flows back into the propellant tank 18 through conduit 57. Needle 58 of needle valve 56 is attached eccentrically to a cam or wheel 60 which may be rotated by any convenient means, preferably an electric motor 63 whose speed may be adjusted. Throttle valve 61 controls the pressure acting on the needle valve and line. The electric motor causes the needle to move up and down periodically into, and out of the conical seat '59 of thevalve 56 making the pressure rise and fall into the propellant feed tube 19, thereby intermittently feeding propellant into the reaction chamber as needle 58 opens andcloses the discharge orifice. The speed of the motor may be regulated by any suitable regulating means, and this will enable the operator to control the speed of propulsion.

The modification shown in FIG. 3 is similar to that in FIG. 1 except that in FIG. 3 the forward end of the reaction chamber is open and provided with an inlet nozzle 28. This permits rapid scavenging of the reaction chamber with Water, since the water can flow into the reaction chamber from both front and back during the intervals between the intermittent periods of high pressure occasioned by the intermittent reactions of the hydrofuel with the water entering the chamber. The front opening 28 facesupstream and the rear opening 16 faces downstream, substantially in the direction of. the longitudinal axis of the duct.

The device shown in FIG. 4 is a modification of the one shown in FIG. 2 in that the forward portion of the reaction chamber is provided with an opening which becomes sealed by a lightly loaded poppet valve 27 seated in opening 26 whenever the pressure within the reaction chamber 15 is greater than the pressure out-side of the reaction chamber, and opens whenever the pressure within the reaction chamber drops below the pressure'of the surrounding medium.

The hydrofuels may be injected intermittently into the reaction chamber in the case of reaction chambers which are closed at one end such as those in FIGS. 1 and 2,

* or may be injected continuously into the reaction chamber in the devices of the type shown in FIGS. 3 and 4.

Reaction chambers in FIGS. 1 and 2 are scavenged by the overexpansion which takes place after each reaction,

the resulting negative pressure tending to suck water back into the reaction chamber as well as'a new charge of hydrofuel which will enter the reaction chamber through the nozzle.

In the operation of the devices according to this invention, water enters the duct through the inlet end 12, passes through the reed valves 14, travels on through the duct and leaves through the exhaust end 13. Some of the water within the duct enters'the combustion cham her @15 where it comes into contact with the hydrofuels therein. Immediately upon contact, spontaneous reaction occurs between the hydrofuel and the water, thereby generating gases of decomposition which, due to their pressure, are forced rearwardly' out the rear opening of be forced down to the rear end 13. The velocity of the water travelling down the tail pipe will reduce the pressure within the chamber and at the front end of the duct, so that the reed valves will automatically open to admit more water in through the front end; and some of the water flowing past the chamber 15 will then come back into the chamber to partially fill it again so that another explosion will occur. The operation will thus occur in a series of intermittent explosions or decompositions, each of which creates the pressure to close the front reed valve and to send the products of decomposition together with the water down through the tail pipe and out the rear; and between each explosion, the reed valve will open to admit water, and more water will enter the chamber.

The hydrofuel may be sent into the combustion chamber either intermittently or continuously. In the case of the devices of FIGS. 1 and 2, the injection of the hydrothen find their own natural timing as established by the dimensions and proportions of the parts. I

In this operation, the function of the directional barrier 16 at the rear of the chambenis to control or restrict the flow of water into the reaction chamber between the explosions. It is ordinarily not desirable completely to fill the reaction chamber with water, but only to admit about as much water as is needed for complete decomposition; and the channel barriers perform this function. Owing to the, directional characteristic of the barriers, however, they do not seriously impede the flow of gaseous products of decomposition in the rearward direction.

In the event that the device is to be driven through the water at high velocity, it may be possible to eliminate the reed valves by proper construction of the inlet portion of the device. When this is done the device then becomes a pulsating hydroduct.

All the hydrofuel reacts completely within the reaction chamber, and only the gases formed by the reaction along with the solid reaction products escape the reaction chamber. These gases and solid products are discharged into the principal body of water flowing through the duct and transfer their energy to the water, forcing it through the exhaust nozzle at elevated velocity.

An advantage in the device according to my present invention is that the reaction chamber is positioned to permit a major portion of the water flowing through the duct tion chamber surface and the subsequent transformation to propulsive energy by an action similar to that which operates in a hydroduct motor.

Other advantages of my invention include an exceptionally efiicient conversion of the thermodynamic energy developed by the reaction between the hydrofuels and 7 water; and this involves the possibility of employing slower reacting hydrofuels than could otherwise be used. Such slower reacting substances, when used in a. hydropulse not involving my present invention would react only partially before being ejected from the exhaust of the duct; and this would involve undesired inefiiciency.

I claim:

1. A jet propulsion device comprising a dncthaving an inlet opening at one end and an exhaust opening at the other end, a combustion chamber within the duct and arranged so that water can flow past it, said combustion chamber having an opening leading into the chamber, a directional barrier placed across the open end of said combustion chamber, said barrier afiording less resistance to fluid flow in one direction than in the other, the direction of greatest resistance being from the outside to the inside of the chamber, means for injecting a hydrofuel into the chamber at a timed rate, and an automatically operative Water inlet valve located across the duct upstream from the chamber opening.

2. Apparatus according to claim 1 in which the means for supplying hydrofuel into the chamber comprises means for injecting solid metal hydrofuel into the chamber.

3. Apparatus according to' claim 1 in which the inlet valve is positioned across the duct upstream from the chamber.

4. Apparatus according to claim 1 in which the inlet valve surrounds the chamber and occupies the space between the outer chamber wall and the wall of the duct.

5. Apparatus according to claim 1 in which the combustion chamber is located symmetrically within the duct so that water flows past it around all sides of it.

6. Apparatus according to claim 1 in which the opening into the chamber faces substantially downstream.

7. A jet propulsion device comprising a duct having an inlet opening at one end and an exhaust opening at the other end, a combustion chamber within the duct and arranged with space between the wall of the duct and the wall of the chamber so that water can flow past the chamber through said space, said combustion chamber having an opening leading into the chamber, a directional barrier placed across the open end of said combustion chamber, said barrier affording less resistance to fluid flow in one direction than in the other, the direction of greatest resistance being from the outside to the inside of the chamber, fuel injection means leading into the combustion chamber, timed means connected with the injection means for injecting hydrofuel into the chamber at a timed rate and an automatically operative water inlet valve located across the duct upstream from the chamber openape 2,252

ins, whereby water in the duct enters said chamber opening and reacts with the hydrofuel producing gaseous products of reaction which drive Water rearwardly out the exhaust opening at a period of repetition established by the timed means.

8. Apparatus according to claim 7 in which the water inlet valve is located around the chamber.

9. Apparatus according to claim 7 in which a second opening is placed in the chamber facing upstream, said second opening being of smaller cross-section than the first-mentioned opening.

10. Apparatus according to claim 7 in which a second opening is provided with a pressure operative valve which opens when the pressure in the chamber is reduced and closes when the pressure in the chamber rises.

11. A jet propulsion device comprising a duct having an inlet opening and an exhaust opening, a combustion chamber within the duct between said inlet and exhaust openings and arranged with space between the wall of the duct and the Wall of the chamber so that water can flow past the chamber through said space, said combustion chamber having an opening providing communication between the duct and the interior of the chamber, the direction of flow through said last-mentioned opening being substantially parallel with the longitudinal axis of the duct, a directional barrier placed across the open end of said combustion chamber, said barrier affording less resistance to fluid flow in one direction than in the other, the direction of greatest resistance being from the outside to the inside of the chamber, means for injecting a hydrofuel into the chamber at a timed rate, and an automatically operative water inlet valve located across the duct upstream from the chamber opening.

12. Apparatus according to claim 11 in which the chamber opening faces downstream.

13. Apparatus according to claim 11 in which there is an additional chamber opening facing upstream.

References Cited in the file of this patent UNITED STATES PATENTS 1,612,794 Bender Jan. 4, 1927 1,980,266 Goddard Nov. 13, 1934 2,461,797 Zwicky Feb. 15, 1949 2,522,945 Gongwer et al Sept. 19, 1950 2,543,758 Bodine Mar. 6, 1951 FOREIGN PAT ENTS 602,807 Great Britain Q June 3, 1948 

